The story of a renovation that went on and on

The advice everyone gives you. And which we followed to the letter

Anyone planning a renovation in Flanders will soon find themselves presented with the same checklist. For example, from Bouwunie, from vinduwaannemer.be, from every construction magazine, or from any well-meaning brother-in-law. It basically boils down to this:

The contractor was local. His other site was literally a five-minute drive from us. His company had been in business since the 1990s, so it hadn’t gone bankrupt in thirty years. The financial figures looked sound. My father had hired him twenty years ago for a small job, with no problems. A reference from within the family is, in theory, even stronger than a stranger from the neighborhood. When we mentioned his name to others, we got a vague “I’ve heard that name before”. No alarm bells rang.

We had a written quote with unit prices. A validity clause. A written confirmation of the start date. We also had an architect, and the works were organized in accordance with best practice. By Bouwunie standards, we were therefore the model client.

And yet.

The stories that only came to light later

It was only when we started saying afterward that things hadn’t gone quite so smoothly that the stories suddenly started coming out. “Ah yes, I’d heard that too.” Someone mentioned that he was already involved in legal proceedings.

In hindsight, we should have questioned all those people much more actively, for example, by asking: “Tell me everything you’ve heard about him, including the rumors.” People are polite. Nobody wants to be the bearer of bad news. Unless you probe further, you’ll only get a vague “hmm, I’ve heard a bit about it”.

Anyway. We’d signed on the dotted line. We’d ticked all the boxes on the checklist.

And so began a six-week renovation that would ultimately last a year and a half.

The first lesson of this whole adventure – and one that might be tucked away in small print at the bottom of a leaflet – is this: simply ticking all the official boxes isn’t enough. It reduces the risk, but it doesn’t eliminate it. If you think that a healthy balance sheet, a local address and a reference from decades ago will protect you from what I’m about to tell you, please read on.

The run-up: a three-month wait

We signed the quote for our renovation in early February 2023. A complete strip of the extension, measuring around 25 m². Demolition, structural work, façade work, flat roof. Nothing out of the ordinary.

The agreement was clear: work would start after the summer building holiday. This was confirmed in writing by the contractor. We had prepared everything: planned the holiday, notified the neighbors, and drawn up a clear schedule. We were ready to go.

He wasn’t: “Yeah, sorry, had to move it a bit.”

He wasn’t there the following week either. Nor the week after that. It wasn’t until three months later that he finally turned up at the site. Unfortunately, the weather wasn’t lovely and summery; instead, it marked the start of one of the wettest spells in years. In the meantime, it turned out he’d been working further down the street on a new-build project that had started after we’d submitted our quote, but which had been given priority over ours.

The second lesson from this whole adventure, which I’d love to see included in every construction guide: a contractor who keeps you waiting before the work even starts will keep you waiting once it’s underway. That doesn’t seem like a coincidence to me. And a year and a half later, I’m more certain of that than ever. Especially if you’re “just” doing a small renovation.

At this point, I should have said: “It’s not needed anymore.”

The Renovation: A Dry-Eyed Recap

The irony of “just” a renovation? How much of it went wrong. Let me give you a quick tour of what went wrong on a six-week construction site. Read it and ask yourself one question: “What percentage of this would I have noticed myself if I hadn’t been working from home?” Because honestly, if I hadn’t been working from home, this would have been a shorter blog post and a much more expensive problem.

The sewer pipe

On one of the days they were removing the old foundation to lay a new one, I noticed mortar around an old GRES sewer pipe—it had cracked right through. Replace it? No way. Just smear some mortar around the crack so it doesn’t stand out. Plan for the next morning: just pour the concrete slab over it. With that broken sewer pipe as a time capsule in the foundation. I asked if this was really wise. Got a clear “yes” in return.

If I hadn’t been there, that crack would now be permanently buried under my new construction, ready to spring a surprise in ten years. After they left, I replaced it myself. Thanks a lot.

The broken tile

Another day, he bumps into my new roof. A tile has cracked. I’m filming them at that moment because I don’t trust the situation. I see him looking at the roof. I keep filming. Later, when asked if anything was broken: “No, I didn’t see anything.”

I have it on video. Literally. And this is someone who’s going to be working with thousands of euros in my backyard.

At moments like that, you learn something about how the conversation about the really expensive stuff is going to go later.

Digging too deep

The agreed-upon depths are 30 cm for the concrete slab and 60 cm for the foundation. In some places, they turned out to be 40 cm deep instead of 30. What do you do then as a contractor? Right, you charge for extra concrete to fill that extra hole. I have to pay because the foreman can’t measure. I was digging on another section myself and got my 30 cm just fine. Discipline—it’s not for everyone.

The rebar I can’t find in the photos

I have photos showing no rebar in part of the foundation. But since walls have been built on top of it in the meantime, it’s hard to prove that now. That’s something that’s bothered me for a long time. Knowing after the fact that something isn’t right and no longer being able to show what’s inside. Rebar isn’t a minor detail.

The support post that doesn’t quite agree with gravity on the left side

A support post is leaning 1 cm. Not much? Enough. In theory, that post needs to be removed and reset. But it’s already cast into the concrete. We’re compensating for it now with a casing, which hides it cosmetically—but the structure itself will never be quite straight. We’ve come to terms with it in the meantime. The house still obeys gravity, after all.

The domes that look across the way

Two domes in the flat roof. When installing them, he shifted them just enough so that the finishing groove of one is behind the concrete slab. A 10 cm thick reinforced concrete slab. To fix this, we’ll have to break open parts of the roof. On top of that, the domes aren’t installed with a slight slope, so water sometimes pools on them.

The roof

The biggest problem of all. The EPDM roofing is loose. The seams aren’t properly finished along the entire length. Just some rubber sealant slapped on top. The slope is so shallow that every time it rains, there are 6-mm-deep puddles all over the roof. When it rains, water sits on a roof that’s supposed to drain. That’s quite an achievement in itself.

The insulation was soaked when he tried to seal it in January. I reported this to him in writing via email. “We’ll keep going.” And that’s exactly what they did. The water? Drilling a hole in the concrete from below!

The missing water barrier

There simply was no water barrier under the bluestone of the sliding windows! We had to point it out to him explicitly. When he installed them, he did it in such a way that the sliding window later didn’t rest properly on the water barrier. We ended up adding an extra water barrier ourselves to fix this.

And then, in his final invoice, he charged for that missing water barrier. €470 for a 6-meter strip that he should have supplied in the first place. I had to read that three times.

The invoice: a fascinating exercise in creative measurement

At the end of January 2024, the final invoice arrived in the mail. €14,898 still to be paid, in addition to the two previous advance payments. Total: over €57,000 including VAT.

I started double-checking the measurements. And I kept double-checking them. And the numbers kept coming out wrong.

A few examples of where I ran into issues:

• The roof. He calculated 35 m². The actual area: 24 m². That wasn’t just a little “rounded up.” He made my house 10 m² bigger.
• Prefab construction. Charged: 3.5 m³. Actual: 2.5 m³. Difference: €450.
• Cavity wall insulation. He calculated 25 m². Actual: 7.79 m². He had conveniently forgotten that the rear facade consisted mainly of windows and doors. Difference: over €900.
• Concrete. Invoiced: 8.5 m³ at €680/m³. Actual work performed: 4.4 m³. Difference: nearly €2,800.
• The missing flood barrier. €470 invoiced for something he was supposed to have delivered anyway according to the quote, and whose installation hadn’t gone entirely smoothly.

I corrected the final bill item by item, using a measuring tape and plans. My own calculation came to €48,964 incl. VAT instead of €57,298. A difference of €8,333.

And that’s giving him the benefit of the doubt in several places. Because, yes, I wanted to be reasonable too.

Disputing an invoice: how to do it officially

Here’s the most important practical advice in this entire post: if you dispute an invoice, do it the right way.

What I did:

1. Registered letter: official, with a date and signature upon receipt.
2. A detailed attachment: with a line-by-line breakdown, my corrections, and the reasons for them.
3. An amount that I did pay as a corrected final statement. The amount you believe is correct. This is very important: you must clearly distinguish between what you are disputing and what you are not.
4. Send in duplicate: once by registered mail, once by regular mail. With registered mail, someone might refuse to sign to drag things out (he did that too; it took until the very last day). The regular mail will arrive regardless.

My letter stated in black and white: “I am now paying you the amount of €6,713.14. This represents the final statement and final invoice as corrected by me. Please find a detailed breakdown attached.”

The response came quite late. An email from the contractor himself containing, among other things, these gems:

“You certainly have no right to unilaterally decide what you want to pay.”

“In the event of non-payment of the remaining amount, further steps will be taken and additional costs and interest will be charged to you. I will then issue an additional invoice for 10% of the total price for materials and labor costs, which have risen in the meantime.”

I’m a bit breathless from the sheer creativity. A 10% extra invoice because prices supposedly went up, even though less than a year earlier he had confirmed in writing that his quoted price would remain unchanged because he had factored in fluctuations in his quote. That’s exactly how he put it himself, in an email I still had. On top of that, his own quote states that prices remain valid for six months. I kid you not, he completely disregarded his own quote to charge me extra.

It illustrates one of the most important lessons: save every email. Even the seemingly trivial confirmation that a price is still valid can be worth its weight in gold a year later.

The mediation: three meetings, two architects, one lawyer too late

I confirmed once again via email that I disputed his calculation. Months later, I received a registered letter from his lawyer. “My client proposes that we meet on-site to reach an amicable settlement.”

I had to take a deep breath here. I had already proposed this to him by paying him fairly for what he had actually delivered. But now he was acting as if he were the conciliatory party. That, in turn, is the art of legal prose.

I decided to accept the proposal anyway. Because: mediation is always cheaper than a lawsuit for both parties.

First site visit

After a month of preparation, we met on-site. He had brought an architect to review the bill of quantities. On his side: an architect, a lawyer (who arrived late), and himself. On my side: myself with my own technical advisor assigned by my legal aid.

And then it turns out: no one had looked at anything. Not his architect, not his lawyer. A month of preparation for nothing. They were only just now starting to read it. On the construction site. Amidst the parapets.

What a waste of time and energy. I had to go through my points one by one right there on the spot. I had to repeat them three times. At one point, his architect made a comment about something she couldn’t see, even though I had sent a photo with measurements two weeks earlier. She simply hadn’t looked at it.

While we waited for the lawyer who was running late, there was a whole explanation about how demanding the profession is and that there are plenty of DIYers who end up with less-than-ideal results. Good point. Just ironic to hear on a construction site where a professional had just been working.

What came of this? That they would go over my calculations and, if necessary, the architect would come by again to take measurements. Do you think she did that? Of course not.

Second site visit

Two months later. Now they had taken measurements. Based on the plans!!

Now they had read it. Now we were finally talking about accurate data.

And then came the magic moment: his architect confirmed the errors.

Not all of them, of course. There were a few points of contention and items I deliberately let slide to move things forward. But the broad strokes were correct. He had overcharged. Substantially so.

At the same time, it was made clear that the roofing work was truly subpar. His own architect admitted that a third of the roof needs to be completely redone, meaning insulation and EPDM. That was something I had already mentioned to him via email back in January when he wanted to close up the roof over wet insulation. But anyway. Better late than never.

“The adhesion of the insulation and the roof membrane is defective. To resolve this issue, one-third of the flat roof’s surface must be redone with regard to the roof waterproofing and the insulation.“

Literally in the settlement agreement. Acknowledged by his own side. Sometimes there’s something satisfying about seeing someone sign their name under a sentence you wrote months earlier.

the settlement: the end

In the end, a settlement agreement was reached. So no lawsuit, but an out-of-court settlement, signed by both parties and legally binding.

The terms:

1. He waives the entire disputed amount. €4,842 incl. VAT—the amount his own architect said he had overcharged? Gone.
2. I will have the roof redone at my own expense. Estimated at approximately €1,704 incl. VAT (8 m² insulation + 12 m² EPDM + 8 m² demolition and cleanup of the vapor barrier).
3. I pay €500 into his lawyer’s escrow account. A symbolic closing of the case.
4. Neither party can make any further claims against the other. A definitive end.

Why did I prefer to have the roof fixed myself rather than let him repair it? Simple: I didn’t want him on my roof anymore. It’s poorly installed, but it doesn’t leak. It’s already weathered two storms. I had a friend who’s an architect check it again afterward, and it’s sturdy enough. I’d rather live with a mediocre roof than have to ask him back onto my house.

Besides, for him, the “repair” would cost roughly its actual cost price, not his selling price. That’s much less painful for him than it is for me to have a third party do it at market rates. So my deal was basically this: I “pay” the difference between the cost price and the market price for the roof, and in exchange, I get the peace of mind that comes with closing the case. Deal.

The numbers: the final tally

For those who want to see the actual numbers:

The latter amount includes the €500 that went into the escrow account. Roof repairs were also deducted from that amount, with an estimated cost of approximately €1,700.

For those who like to look at the bigger picture, the contractor paid at least that amount in legal and architectural fees that he couldn’t pass on. For him, this was likely a much heavier financial blow than it was for me. At a certain point, that bill is the only language that works.

Taking a step back: what this story really tells us

Before I get to the tips, I want to make one point clear, because it’s probably the very reason I’m writing this in the first place.

I spent a year and a half working on a case that resulted in a correction of nearly €8,000 on the final invoice, acknowledged by the opposing party’s architect himself. By his own architect, following an on-site re-measurement, documented in an official document that formed the basis of the settlement.

That is no small difference. For specific items, the discrepancies ranged from 30% to 50%: the roof was billed for 35 m² instead of 24 m², and cavity insulation for 25 m² instead of 7.79 m². Simply measurements that do not match reality.

Now imagine this: a homeowner with no time, no expertise, and worse yet, no legal representation. That person would have simply paid the €57,000. Because what are you going to do? File a lawsuit for €8,000 when legal fees alone run €2,000 to €3,000?

The structural problem

That’s the crux of the matter. The system of unit prices with a post-construction bill of quantities only works if the contractor measures honestly. If he doesn’t, the burden of proof lies entirely with the client. Someone who typically isn’t a surveyor, has no time, and without insurance also has no access to affordable legal advice. The threshold for disputing the bill is high, while the threshold for simply paying it is low. And that’s what they count on.

I’m not claiming that every contractor uses unit prices to inflate costs. Far from it. There are those who measure correctly, deliver good work, and send a fair invoice. But the system simply allows those who want to exploit it to do so with minimal risk because most clients won’t dispute it.

That is what has stayed with me most from this entire case. Not the anger toward one person, but the realization of how many other homeowners there are who have quietly overpaid without ever knowing it. To help others avoid similar problems, I would like to offer the following tips.

The lessons: what I want to pass on to you

Here comes the most important part. Because if you’re reading this and facing a similar situation on your site, these ten points could save you a lot of trouble.

1. Get comprehensive legal cover. Right now.

Not when you’re about to start building. Right now, before you even start thinking about a renovation. Most policies have a long waiting period. For a few hundred euros a year, you get cover for things like this, and in my case, it has literally saved me thousands of euros. My letter of objection, my preparations, my legal advice, all communication with his solicitor – all covered. No out-of-pocket costs. For that reason alone, it’s the best value insurance you could ever take out.

2. Document EVERYTHING, right from day one

• Photos of the site every day, with the date and time stamp.
• Video footage of demolition and concrete pouring. Focus particularly on the foundations and reinforcement. Once it’s in the concrete, you can never prove what was in it.
• Emails about everything. Agreed over the phone? Confirm in writing: “Dear [name], just to be clear: we’ve just agreed that…”. If they don’t reply, you’ll still have proof that this is how you understood it.
• Keep every quote, every version, every amendment. With the date.

3. Be present on site; literally

I work from home, and without that I wouldn’t have spotted a whole host of problems. If you can’t work from home, do at least take a few days off at critical stages (excavation, foundations, roofing). It sounds extreme, but it’s a cheap way to protect yourself against irreversible mistakes.

4. Pull the emergency brake if you see a delay

A contractor who makes you wait three months before starting the work is likely to keep you waiting in the future too. That pattern of saying “I’ll be there tomorrow”, which turns into “tomorrow”, then “next week”, and then “after the weekend”, is a way of working. If you spot this before the work even begins, you should think twice. Invoking a termination clause is painful, but less painful than waiting a year for someone who never turns up.

5. Understand the difference between fixed prices and unit prices

A “breakdown based on unit prices” is not a fixed total price. The price per unit (per m², per m³, per kg) is fixed, but the number of units is measured and charged retrospectively. This is where the creativity of a less scrupulous contractor comes into play. He overestimates. He forgets that a wall is actually a window opening. He measures the outside rather than the inside.

Tip: If possible, ask for a quote with a fixed total price (lump sum) for clearly defined work, not unit prices. Or at the very least, take your own measurements before agreeing to the contract.

6. Check everything yourself before you pay

This may sound obvious, but it’s rarely done. Have you received a final invoice? Check that the work actually carried out matches the invoice before you pay; you’ll lose your bargaining power. Compare the quote with the actual work item by item. It’ll take you half a Saturday and could save you thousands of euros.

7. Disputed by registered letter, with a detailed breakdown

If the numbers are incorrect, please file a formal objection:

• Aangetekende brief én gewone post.
• Detail per post: wat hij rekende, wat het werkelijk is, en waarom je dat zegt.
• Betaal het bedrag dat volgens jou correct is met duidelijke vermelding dat dit voor jou de eindafrekening is.
• Hou er rekening mee dat het werk geleverd moet zijn volgens goed vakmanschap. Fouten mogen niet aangerekend worden.

8. Expect a lawyer. Don’t be intimidated.

If the contractor isn’t a complete fool, he’ll hire a solicitor. They’ll write fancy letters full of pompous language and threats. Read them, don’t let yourself be intimidated, and forward them to your legal aid. They’ll then assist you. It’s not your stress.

What helped me most mentally: realize that the other party is doing the maths too. Every letter from his lawyer costs him hundreds of euros. Every site visit with an architect costs him even more. At a certain point, it becomes more rational for him to drop the claim than to press on.

9. Know your (and their) limit(s)

For amounts under €1,000, taking legal action is usually not cost-effective. Not just for you, but for him as well. For amounts of €5,000 or more, it does become worth considering. In the middle range, a settlement agreement (out-of-court settlement) can save everyone time, money and stress. That’s what we did, and to be honest: it was the best option.

Don’t go for 100% justice. Go for sufficient justice. In my case, I received the majority of the disputed amount, plus no further dealings with the contractor. That was more than enough.

10. You give up when you give in

The most important thing, and the hardest: see it through. If he notices you’re starting to waver:

• Your replies become shorter
• You let deadlines slip,

then he’ll smell blood. He’ll drag the case out further, hoping you’ll give up.

Don’t give up. Keep your communication tight and businesslike, with your legal counsel involved. It will be frustrating. It will take a long time. (In my case: six months from dispute to settlement). But if you have your case in order, you will force a fair settlement. Almost certainly.

Was it worth it?

Yes. Without a doubt, yes.

Not just for the money, although that was substantial. But for the feeling that you don’t have to come off worse simply because the other side is counting on your exhaustion. There’s also the realisation that you don’t have to accept whatever a professional puts before you, simply because they’re supposed to be a professional. And finally: the experience that a solid case file, patience and comprehensive legal support outweigh ten years of construction experience on the other side.

Was it stressful? Absolutely. Did it take time? Yes, a lot of time. Days off when I would rather have done something else. Plus evenings spent poring over photos and measurement reports. But if I had to do it all over again, with exactly the same contractor, on exactly the same site, I would do exactly the same thing.

With one small difference. I wouldn’t have chosen him.

Does this story sound familiar to you? Please feel free to share it. And for those of you going through this right now: hang in there. Keep a record of what’s happening. Ask for help. You don’t have to go through this alone.